HAM TV

1. HAM TV is too difficult.  Well, because PC Electronics has been
   building HAM TV equipment exclusively since 1965 - 45 years! -
   HAM TV is now "plug-and-play."

2. HAM TV is too expensive.  Well, if you already have a video
   camera and a TV set capable of picking up the analog cable
   channels AND if you already have a vertically polarized 70 cm
   beam a HAM TV transmitter can be bought new for less than
   $300.00.  However, since many HAM TV repeaters are cross band -
   70 cm in and 1.2 GHz out - you will also need a 1.2 GHz down
   converter and beam antenna - but the AATV repeater on Shaw
   Butte is INBAND - which means the input and output are both IN
   the 70 cm band.

3. Can I use my 70 cm FM radio for HAM TV?  No, for several
   reasons:

a. Most 70 cm radios only cover 440 to 450 MHz and the TV is below
   that.
b1. Most 70 cm radios are narrow band - each channel is only 25
    kHz wide.  That gives you a max of 400 channels.
b2. All HAM TV in the 70 cm band is AM and not FM - each channel
    being a minimum of 6 MHz wide - the equivalent of 240 FM
    channels.

4. HAM TV is a band hog.
a. Well, if you want to be able to HEAR the fellow you are
   watching (and who doesn't?) NTSC standards (US analog TV) -
   which almost all of us use - require that the audio has to be
   4.5 MHz "above" the video carrier.  In fact, the amateur rules
   (Part 97) quote the broadcast TV rules (Part 73) for standard
   HAM TV.
b. So long as the +/- 1 MHz around the video carrier and +/-100
   kHz around the color and audio subcarriers are protected
   there's almost no instantaneous RF within that 6 MHz TV
   channel.

NOTE: I've pointed my 10 watt TV transmitter and my 10-element
beam DIRECTLY at a ham satellite operator and, with his satellite
receiver (435-438 MHz) he couldn't even tell I was there!
However, as soon as he turned on his TV - there I was.

So, we start with 240 25 kHz channels, subtract 80 for the video,
8 for the color and 8 more for the audio and that leaves us with
224 25 kHz channels that have to be protected.  You can put 16
more 25 kHz FM voice channels INSIDE the 6 MHz band width! Add
that to the 400 FM voice channels between 440 and 450 and you have
16 MORE channels that could be used - assuming that ALL 400 were
already used.

I'm not an expert - but I play one on HAM TV.

Bil Munsil
K1ATV HAM TV
Mesa AZ
Always remember - Hams should be SEEN as well as heard!